(CNN) -- More than 30,000 people have fled their homes ahead of an expected eruption of the Mayon volcano in the central Philippines, the Red Cross said Wednesday.

Philippine authorities have said a large-scale eruption of the 2,464-meter (8,077-foot) peak is imminent, and have begun trying to evacuate about 50,000 people living around the nation's most active volcano.

Gwendolyn Pang, the secretary-general of the Philippine Red Cross, said the ground around the mountain shook several times Wednesday. Emergency workers have so far evacuated 30,751 people, with 21 centers set up to take in the evacuees, she said.

People in surrounding Albay province have flocked to town centers to catch a glimpse of glowing lava cascading down the slopes of Mayon since the mountain began oozing fiery lava and belching clouds of ash this week.

The Philippine Institute of Volcanology and Seismology raised its alert level for the Mayon volcano Monday night, warning that a full-scale eruption could occur "within weeks to days." The volcano, about 500 kilometers (310 miles) south of the Philippine capital Manila, has gone off 49 times since the first documented eruption in 1616.

The Philippines is in the so-called Ring of Fire, an arc of fault lines circling the Pacific Basin that is prone to frequent earthquakes and volcanic eruptions. Mayon's most violent eruption, in 1814, killed more than 1,200 people and devastated several towns. It's last major eruption was in 1993.